Product Description
MBRP M1004 is the classic Quiet Tone universal muffler built for 4" diesel systems. This T304 stainless (Armor Pro) version delivers a mellow, drone-controlled note without choking flow. Perfect for daily drivers and tow rigs that want civilized sound and long-term durability in harsh climates.
- Material: T304 stainless steel (Armor Pro)
- Size: 4" inlet / 4" outlet
- Case: 24" body length • 6" case diameter
- Overall length: 30"
- Design: Quiet Tone chambering to reduce rasp and in-cab drone
- Install: Weld or band-clamp into any 4" section; maintain correct flow direction
Fitment
Universal for any 4-inch diesel exhaust system (Cummins, Duramax, Power Stroke, and custom builds). Ensure you have 30" straight section length and 6" of case clearance. Fits most 4" turbo-back and cat-back kits that use a 30" muffler body.
Recommended MBRP Cross-Reference / Alternatives
- Stainless T409 Quiet Tone: MBRP M1004S
- Aluminized Quiet Tone: MBRP M1004A
- T304 “replace-all 30"” universal (Armor Pro): MBRP M1031
- High-flow (louder) option: MBRP GP015
Helpful Notes
- Use quality Torca band clamps for leak-free installs; verify hanger spacing after positioning.
- For maximum corrosion resistance (salt states), T304 is preferred over T409 and aluminized steel.
FAQ
Will this fit my truck without additional adapters?It’s a universal 4" muffler with 30" overall length. Most 4" diesel systems accept it directly; some may need minor trimming or an adapter depending on where the muffler sits in the system.
How quiet is the Quiet Tone compared to stock?
It lowers drone and harshness versus many straight-through performance mufflers while keeping a deeper, performance-oriented note. Overall volume is typically above stock but comfortable for towing and daily use.
What’s the difference between T304 and T409 stainless?
T304 offers the highest corrosion resistance (great for road salt or coastal areas). T409 is durable and cost-effective but can show surface oxidation over time.
Is there a direct MBRP T304 alternative if M1004 is unavailable?
Yes — MBRP M1031 is a T304 stainless, 30" overall muffler that replaces most 4" 30" units.
Does direction matter when installing?
Yes. Follow the indicated flow arrow or orient the internal chambers correctly for best sound control and performance.
